The present invention relates to a power train which is particularly suitable for use in an amphibious vehicle capable of travel on land and water, and more particularly to a means of adapting a conventional automotive transaxle drive arrangement to drive the wheels and the marine propulsion means of an amphibious vehicle. The invention also relates to an amphibious vehicle having such a power train.
In some automotive power train arrangements the engine has a crankshaft in line with the longitudinal axis of the vehicle, whereby the engine drives an in-line transmission with an integral differential which is typically located between the engine and the transmission, the differential being connected by drive shafts to the drive wheels of the vehicle. This arrangement is commonly known as a transaxle drive and has been employed in front engine, rear engine and mid engine power train layouts.
It is also known for transaxle power train arrangements to be adapted to provide four wheel drive. In such known four wheel drive arrangements, the transaxle will typically drive the front wheels of the vehicle, with a power take off from the transmission driving the rear wheels of the vehicle.
The transaxle drive arrangement is currently used by several large car manufacturers in the production of private passenger vehicles and is therefore produced in relatively high volumes, which makes the arrangement most procurable for use in an amphibious vehicle. In choosing a power train for a specialised low volume production vehicle, such as an amphibious vehicle, availability is an important factor.
EP 0 742 761 discloses a power train for an amphibious vehicle using a front wheel drive power train reversed, to mount the engine behind the rear axle. The marine power take off is by a gearbox taken from the timing end of the engine, opposite to the transmission mounting end. This power take off requires a number of custom designed parts to be designed, built, and assembled; and may require redesign and relocation of engine mounted accessories, such as the alternator drive belt. Also, the reversal of the power train may require additional gearing or other modifications to ensure that the road wheels rotate in the required and expected directions. The cost burdens and assembly requirements of such adaptations are particularly unwelcome to low volume vehicle manufacturers.